Top 50 Math Problems for 8th Graders
- Author: Noreen Niazi
- Last Updated on: February 21, 2024
Mathematics is the necessary building block of our understanding of practically numerous concepts in different fields. For 8th graders, it must be at the forefront of their mind that they solidify basic mathematical principles so they can excel in their academic pursuit and postsecondary career. This guideline contains the top 50 number problems that cover different areas of mathematics that include geometry, algebra, percentages and ratios, statistics and trigonometry. Sections cover examples, detailed procedures, questions and answers, and practice with solutions to facilitate understanding and learning.
Geometry Problems for 8th grader
Geometry deals with the analysis of characteristics of shapes, sizes and properties of bodies. Here are ten problems to challenge your geometric prowess:Here are ten problems to challenge your geometric prowess:
15 Challenging Geometry Problems and Their Step-by-Step Solutions Introduction to Geometry Problems The area of mathematics known as
1
Calculate the perimeter of a rectangle with length $$8 cm$$ and width $$5 cm.$$
As we know that perimeter of rectangle is equal to two times the sum of length and width of rectangle.
Here
$$length =8cm$$
$$Width= 5 cm$$
Therefore
$$Perimeter = 2(length + width)$$
$$Perimeter = 2(8 + 5)$$
$$= 2(13) = 26 cm$$
2
Find the area of a triangle with base $$6$$ cm and height $$9$$ cm.
As we know that
$$\text{Area of triangle }=\frac{1}{2} \times \text {base} \times \text{height}$$
$$Area = 0.5(base × height)$$
$$Area = 0.5(6 × 9)$$
$$= 0.5(54) = 27 sq. cm$$
3
Determine the volume of a cube with side length 4 cm.
As we know that
$$\text{Volume of cube }=\text {sides}^3 $$
$$\text{Volume}=4^3$$
$$\text{Volume}=64cubicm$$
4
What is the circumference of a circle with radius $$10 cm$$? (Use $$\pi = 3.14$$)
$$Circumference = 2πr$$
$$Circumference = 2 × 3.14 × 10$$
$$= 62.8 cm$$
5
Calculate the surface area of a sphere with radius $$6 cm$$. (Use $$\pi = 3.14$$)
As we know that
$$\text{Surface area of sphere }=4 \pi r^2$$
$$ 4 × 3.14 × 6² = 452.16 sq. cm$$
6
Find the missing angle in a triangle with angles measuring 45° and 75°.
Sum of angles in a triangle = 180°
Missing angle = 180° – (45° + 75°) = 60°
7
Determine the diagonal of a square with side length 12 cm.
Diagonal = side × √2
Diagonal = 12 × √2 ≈ 16.97 cm
8
Calculate the area of a trapezoid with bases 7 cm and 9 cm, and height 8 cm.
Area = 0.5 × (sum of bases) × height
Area = 0.5 × (7 + 9) × 8 = 64 sq. cm
9
Find the volume of a cylinder with radius 5 cm and height 10 cm. (Use π = 3.14)
Volume = πr²h
Volume = 3.14 × 5² × 10 = 785 cubic cm
10
Determine the area of a parallelogram with base 10 cm and height 12 cm.
Area = base × height
Area = 10 × 12 = 120 sq. cm
An Easy Way of Translating Words into Algebraic Expressions As a math teacher, I frequently meet students who
Algebra Problems for 8th graders
Algebraic concepts form the backbone of mathematics’ They allow us to solve equations and analyze patterns. Here are ten algebra problems to sharpen your skills:
11
Simplify the expression: 3(x + 4) - 2(2x - 5)
3(x + 4) – 2(2x – 5)
= 3x + 12 – 4x + 10
= -x + 22
12
Solve for x: 2x - 5 = 3(x + 1)
$$2x – 5 = 3(x + 1)$$
Firstly we solve bracket and multiply 3 inside.
$$2x – 5 = 3x + 3$$
Subtracting $$3x$$ from both side.
$$-x = 8$$
$$x = -8$$
13
Factorize the quadratic expression: x² + 5x + 6
$$x² + 5x + 6 = (x + 2)(x + 3)$$
14
Find the value of y when x = 3 in the equation: 2x + 3y = 12
2(3) + 3y = 12
6 + 3y = 12
3y = 6
y = 2
15
Solve the system of equations: 2x + y = 10 x - 3y = 5
Using substitution or elimination methods, the solution is x = 4, y = 2.
16
Simplify the expression: (2x²y³)⁴
(2x²y³)⁴ = 2⁴x⁸y¹² = 16x⁸y¹²
17
Solve the inequality: 3x - 7 < 2x + 4
3x – 7 < 2x + 4 x < 11
18
. Find the product of (x + 2)(x - 2)
(x + 2)(x – 2) = x² – 4
19
Solve the equation: 5(2x - 3) = 7x + 10
10x – 15 = 7x + 10
3x = 25
x = 25/3
20
Find the slope of the line passing through points (3, 4) and (5, 7)
Slope = (change in y) / (change in x) = (7 – 4) / (5 – 3) = 3/2
Mastering Percent Word Problems in 2023: Tips and Tricks for Success Do you know how percent marks you
Percentage and Ratios Problems for 8th Graders
Understanding percentages and ratios is essential for interpreting data and solving real-world problems. Here are ten problems to test your proficiency:
21
What is 20% of 150?
20% of 150
= (20/100) × 150 = 30
22
Express 3/5 as a percentage.
(3/5) × 100% = 60%
23
If a shirt originally costs $40 and is now on sale for 25% off, what is the sale price?
Sale price = $40 – (25% of $40) = $40 – (0.25 × $40) = $30
24
If a recipe calls for 2 cups of flour to make 12 cookies, how many cups of flour are needed to make 24 cookies?
Proportion: 2 cups / 12 cookies = x cups / 24 cookies x = (2 × 24) / 12 = 4 cups
25
If the ratio of boys to girls in a class is 3:2 and there are 20 boys, how many girls are there?
Let the number of girls be x. (3/2) = 20/x x = 2(20/3) = 40/3 ≈ 13.33 (approximated to nearest whole number) There are approximately 13 girls.
26
A car travels 240 miles on 12 gallons of gas. What is the miles per gallon (MPG)?
MPG = Total miles / Total gallons = 240 miles / 12 gallons = 20 MPG
27
If 30% of the students in a school are girls, what percentage are boys?
100% – 30% = 70% So, 70% of the students are boys.
28
In a bag of 80 marbles, 20% are red. How many red marbles are there?
20% of 80 = (20/100) × 80 = 16 marbles
29
If a rectangle has a length of 12 cm and a width of 8 cm, what is the ratio of length to width?
Ratio = Length : Width = 12 cm : 8 cm = 3 : 2
30
If a pizza is cut into 8 equal slices and 3 slices are eaten, what fraction of the pizza remains?
Fraction remaining = (8 – 3) / 8 = 5/8
Statistics Problems for 8th Graders
Statistics involves the collection, analysis, interpretation, and presentation of data. Here are ten problems to enhance your statistical skills:
31
Calculate the mean of the following set of numbers: 5, 8, 12, 15, 20.
Mean = (5 + 8 + 12 + 15 + 20) / 5 = 60 / 5 = 12
32
Find the median of the data set: 7, 10, 15, 18, 22, 25, 30.
Since there are 7 numbers, the median is the 4th number, which is 18.
33
Determine the mode of the following numbers: 3, 4, 6, 6, 8, 8, 8, 9.
Mode = 8 (as it appears most frequently)
34
Calculate the range of the data set: 4, 8, 10, 15, 20
Range = Largest number – Smallest number = 20 – 4 = 16
35
If the probability of winning a game is 0.25, what is the probability of losing?
Probability of losing = 1 – Probability of winning = 1 – 0.25 = 0.75
36
In a survey, 60% of people preferred chocolate ice cream, 30% preferred vanilla, and the rest preferred strawberry. What percentage preferred strawberry?
100% – (60% + 30%) = 10% preferred strawberry.
37
A box contains 20 red balls, 15 blue balls, and 10 green balls. What is the probability of randomly selecting a blue ball?
Probability of selecting a blue ball = (Number of blue balls) / (Total number of balls) = 15 / (20 + 15 + 10) = 15 / 45 = 1/3
38
In a class of 30 students, the mean score on a test is 75. If one student with a score of 95 joins the class, what is the new mean?
Total score = 75 × 30 = 2250 New total score = 2250 + 95 = 2345 New mean = 2345 / 31 ≈ 75.65
39
If the standard deviation of a data set is 10, what percentage of the data falls within one standard deviation of the mean?
Approximately 68% of the data falls within one standard deviation of the mean
40
A dice is rolled 60 times, and the number 3 comes up 12 times. What is the experimental probability of rolling a 3?
Experimental probability = (Number of times event occurs) / (Total number of trials) = 12 / 60 = 1/5
Simplifying Right Triangle Trigonometry: Tips and Tricks Do you ever listen to right-angle triangles? If yes, then you
Trigonometry Problems
41
Find the sine of a 30-degree angle.
sin(30°) = 1/2
42
Calculate the cosine of a 60-degree angle.
cos(60°) = 0.5
43
Determine the tangent of a 45-degree angle.
tan(45°) = 1
44
Find the value of sec(30°) using the reciprocal identity.
sec(30°) = 1 / cos(30°) = 1 / (sqrt(3)/2) = 2 / sqrt(3) = 2sqrt(3) / 3
45
Calculate the cosecant of a 60-degree angle
cosec(60°) = 1 / sin(60°) = 1 / (sqrt(3)/2) = 2 / sqrt(3) = 2sqrt(3) / 3
46
Determine the cotangent of a 30-degree angle.
cot(30°) = 1 / tan(30°) = 1 / (1/sqrt(3)) = sqrt(3)
47
Find the length of the side opposite a 45-degree angle in a right triangle with a hypotenuse of 10 units.
Using the sine function, opposite side = hypotenuse × sin(45°) = 10 × (1/sqrt(2)) = 5sqrt(2)
48
Calculate the measure of angle A in a right triangle where side a = 5 units and side b = 12 units.
Using the sine function, opposite side = hypotenuse × sin(45°) = 10 × (1/sqrt(2)) = 5sqrt(2)
49
Calculate the measure of angle A in a right triangle where side a = 5 units and side b = 12 units.
tan(A) = opposite / adjacent tan(A) = 5 / 12 A = tan^(-1)(5/12) ≈ 22.62°
50
Given two sides of a triangle, a = 8 units and b = 15 units, find the measure of the included angle C.
Using the cosine rule:
$$c^2 = a^2 + b^2 – 2abcos(C)$$
$$c^2 = 8^2 + 15^2 – 2(8)(15)cos(C)$$
$$c^2 = 64 + 225 – 240cos(C)$$
$$c^2 = 289 – 240cos(C) cos(C) = (289 – c^2) / 240$$
Given c = sqrt(289), we can find cos(C) and then angle C.
Viral Math Problems for 8th Graders
Geometry Problem:
Viral Problem: A square is inscribed in a circle with radius 5 cm. What is the area of the square?
Solution: The diagonal of the square is equal to the diameter of the circle, which is 2 * radius = 2 * 5 = 10 cm.
Using the Pythagorean theorem, the side length of the square can be found: side² + side² = diagonal²
2(side)² = 10²
(side)² = 100 / 2
(side)² = 50 side = √50 ≈ 7.07 cm
The area of the square = side * side = 7.07 * 7.07 ≈ 50 sq. cm.
Algebra Problem:
Viral Problem: If , what is the value of x?
Solution: To add fractions, find the least common denominator, which is 12.
Multiply both sides by 12 to isolate x. Divide both sides by 7.
Percentage and Ratios Problem:
Viral Problem: If a shirt originally costs $50 and is now on sale for 20% off, what is the sale price?
Solution: Original price = $50 Discount = 20% = 0.20 Amount of discount = 0.20 * $50 = $10 Sale price = Original price – Discount Sale price = $50 – $10 = $40
Statistics Problem:
Viral Problem: In a class of 30 students, the mean score on a test is 75. If one student with a score of 95 joins the class, what is the new mean?
Solution: Total score before new student = 75 * 30 = 2250 New total score = 2250 + 95 = 2345 New mean = New total score / Total number of students New mean = 2345 / 31 ≈ 75.65
Trigonometry Problem:
Viral Problem: If tan(A) = 3/4, what is the value of sin(A)?
Solution: Given that Use the Pythagorean identity: So,
Taking square roots,
Now, So,
Finally,
These are just a few examples of viral math problems that have garnered attention due to their intriguing nature and widespread appeal.
Practice Question
- Simplify: 5x + 3y – 2x – 4y
- Solve for x: 2(x – 7) = 3(2x + 4)
- Factorize: x² – 9
- Find the mean of the data set: 10, 15, 20, 25, 30
- Calculate the median of: 8, 10, 12, 15, 20, 25
Explore Grade 1 Math Curriculum: A Comprehensive Guide Grade 1 starts off as a child’s introduction to the
FAQs
Commence by simplifying both sides of the equation, isolating the variable and carry out the same operations on both sides to keep the equation equal.
Convert percentages into decimals (e.g. 20% = 0.20) and multiple them by the given number.
Try textbooks, math websites online, worksheets and also tutoring services if you need additional practice and guidance.
Use them as much as possible, understand the methods of their proofs, and utilize mnemonic tools or pictures to memorize them.
Conclusion:
Solution to practice questions
- 3x – y
- x = -5
- (x – 3)(x + 3)
- Mean = 20
- Median = 13.5
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